Water. It comprises more than two-thirds of the weight of the human body and nearly 95 percent of your brain. You need it to live, and hopefully, you're consuming between 2-3 liters of water a day. But if you are, what else are you drinking? What is in your well and what microscopic baddies have hitched a ride on your H2O? The DIY experts at Stack Exchange offer a few tips on spotting contaminents in your drinking water.

Question:

Answer: Call The Pros

"Water quality" is not one-dimensional ... what kind of contaminats do you want to test for?

If the answer is either "everything" or "I don't know" then start by finding a reputable local lab, describe your concerns to them, and see what they recommend based on their knowledge of the water in the area. Once you have done a thorough one-time test, you will have a basis for deciding what (if anything) to test for on an ongoing basis.

To find a lab, start by calling the water authorities in your town or surrounding towns. At least in my case, they were happy to recommend a local, independent lab.

Answer: Test For Yourself

You can buy a test kit from your local home center or online. The kits usually come with a package of strips that contain reactants that change color to indicate the presence of various contaminants in your water.

But beware: the kits are not terribly accurate, and they don't test for all harmful contaminants. If there are very high levels of certain contaminants in your water, the kit very well may flag the problem. But don't expect high accuracy or a guarantee that your water is safe.

The best bet if you are concerned about the quality of your water: Find a reputable, independent lab, which will provide accurate results and have no vested interest in selling you an expensive filtration system.

Lead
- Can be caused by leaded solder, and old brass plumbing components.
- A neurotoxin which is quite dangerous to drink

Sand or grit

Most jurisdictions have their own set of guidelines for acceptable levels of about a hundred different attributes (eg, here are the EPA contaminants limits, to my knowledge in North America, local standards are at or below these levels).

There are currently (to my knowledge, at least) no continuous processes for checking bacteria — though I do know of at least one company who has been working on it for commercial applications (I would guess it would cost upwards of $20k). There are some sensors that can monitor other attributes. Most are prohibitively expensive for a home.

Here's the thing though - most of the quality attributes are unlikely to change, definitely not fast enough to actually monitor on your house. Contamination from bacteria can increase over time if your well is biofouled as the bacteria grows, but otherwise, unless you have a source of surface contamination (such as a poorly-constructed well that is not sealed properly, a dug well, or a well with direct influence from a body of water) then generally, the water quality will be fairly steady.

One option for home testing is a water test kit (such as those that SenSafe makes). These are relatively cheap, and you can quickly conduct the tests at home. But be careful: it's not really possible to measure your water quality or safety using just water quality test strips. They can help give you an idea of what's in your water, and check that your treatment is working, but you should never base the cleanliness of your water on test strips alone. Talk to a professional that understands the chemistry of the water and how all the different factors interact to come up with treatment options.

The EPA has a decent site about Private Wells, you may want to check it out for more information.